We are currently having a blank page when doing a checkout from our store. We upgraded to version v156 last fall and most likely it has been like that since then.

We mostly used our online store to show our product and our customer come in the store to browse and buy since we sell lawn equipment.

When trying to checkout after adding items to the cart, we get a blank page.

I would like to try do debug myself but I can't find on the server any log files which would give me some clues.

Where are those log files and/or is there a way to set a debug mode so that I would get more information. Thanks

our URL is mrbss.ca, and Zencart is under the Online Store tab.